It is generally accepted that shear force during mashing, transferring and lautering should be avoided, especially in the case of thin-bed filtration, using a fine milled grist. Therefore pump rotation speed is limited up to1000 rpm during thin bed filter operations.
However, in order to achieve the targets of flow, filtration pressure, and low rotation speed, the transfer pump is mostly too large and operates far from the BEP (Best Efficiency Point). The peripheral speed/velocity at the outside diameter of the impeller is defining the pressure. To achieve a certain pressure a corresponding peripheral speed is needed. A lower speed of rotation results in a larger impeller diameter to achieve the same peripheral speed and related pressure.
In this study, the phenomenon has been tested for mash transfer during thin bed filtration. Tested on pilot scale and industrial scale.
